Furnace



Nov. 2, 1943. w. FERGUSON FURNAGE Filed Dec. 30, 1941 n, mm, W

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Patented Nov. 2, 1943 FURNACE William Ferguson, Philadelphia, Pa., assignor to National Airoil Burner Company, Incorporated, a corporation oil-Delaware Application December 30, 1941, Serial No. 424,961

6 claims.. (c1. 15s-11) The invention relates to furnaces.

The object is to provide method and means for facilitating the combustion of fuel gas and atomized fuel oil, either separately or combined, with maximum heating eiciency.

The invention relates especially to a fuel gas burner and an atomizing fuel oil burner vcombined, in a single structure and adapted to burn both of said fuels at the same time or to burn either fuel separately.

'I'he invention comprises improved method and means whereby the ame of the fuel gas is projected into the furnace, while atomized fuel oil is projected into the gas ame, and whereby a percentage of the required combustion airis entrained through the burner to be mixed with the atomized fuel oil, and whereby secondary combustion air, under adjustable control, is delivered to said fuel at a point adjacentthe point of entry of the fuels to the furnace.

The invention also comprises improved method and means whereby the delivery of secondary air is subjected to such control as to deliver it predominately in different horizontal planes.

The invention also comprises improved method and means whereby the several flows of fuel gas, fuel oil, preliminary combustion air and secondary air are al1 subject to independent control for whatever coordination desired.

The invention also comprises means forming a nozzle common to the discharge of both fuels, and so formed as to prevent flame are-back in the gas burner and at the same time retaining ignition, said ame retention nozzle so constructed as to protect the burner parts from destructive heat radiation.

The invention also comprises improved method and means whereby a hot zone is created into which the combustible mediums are projected, for stimulating the mixing of the fuel with secondary combustion air.

The invention also comprises a burner block and a muilie block in tandem and adjustable means for delivering secondary air to said blocks, said delivery predominating in different areas, (such as upper and lower) of said blocks.

- The invention also comprises means, such as a tubular housing permanently fixed within the airovent burner structure for receiving the fuel oil burner pipe, and for permitting its withdrawal at any time without interfering with the operation of the fuel gas burner.

Referring to the drawing, which illustrates merely by way of example, suitable means for the embodiment of my invention:

i fuel oil burner combined with the fuel gas burner structure.

Fig. 4 is a fragmentary elevation. I

Similar numerals refer to similar parts throughout the several views.

The airovent fuel gas burner is of the usual inspirating type, using a Venturi tube I I, through which from 40 to 90% of the total required combination air is `inspirated by means of the gas pressure.

The gas is delivered through the tubular body I2 connected to a fuel gas supply pipe I3. This pipe I3 is preferably provided with a suitable gas valve I 4 and also a pressure gage l5.

The tubular body I2 is provided at its discharge end with a gas orifice formation I6 provided with a discharge orifice 20.

The venturi I I is connected at its discharge end to an elbow I'I, to which is connected a pipe or nipple I8, the axis of which is at right angles to the axis of the venturi. The nipple I8 delivers to and through the flame retention nozzle I9 which is secured on the pipe nipple I8.

The elbow connection with the venturi makes it possible to keep the burner close to the furnace wall.

The intake end of the Venturi burner II, into which the gas orifice I6 discharges, is provided with an air-shutter 2I which is adjustable by means of the knurled headed screw 22, for controlling the amount of inspirated air which is mixed with the fuel gas within the burner tube.

The flame retention nozzle or burner head I9 delivers the gas flame from the Venturi burnertube Il to the burner block 23, and is adapted to avoid the flare back in the gas burner and at the same time maintaining ignition. This burner block also insulates the nozzle I9 from excessive and destructive heat radiation.

When gas is burned, as already stated, it will inspirate from 40 to 90% of the total'required combustion air through the venturi II, and discharge it through the flame retention nozzle I9 into the burner block 23, whence the fiame is projected into and through the muiile block 24 to the furnace, while secondary air, in the necessary volume to complete combustion, is admitted through the adjustable secondary air doors 25 in the front wall 38 of the furnace.

In combination with the airovent gas burner I have provided a fuel oil burner or oil burning means associated with the structure of the gas burner.

In the example shown herein I have provided a steel tube 21 extending axially through the elbow I1, nipple |8 and flame retention nozzle I9, to or 'near the discharge end of said nozzle I3. This tube 21 is permanently supported and centered by the four centering spokes, as at 28, in the nipple I8 midway its extension; and near its outer end is supported and positioned by the bushing 29, in the wall 30 of the elbow |1--sald steel tube extending outwardly beyond the wall of the elbow. This steel tube 21 is adapted to receive the fuel oil burner pipe 3|, which is connected with an oil supply pipe 32, controlled by the oil regulating valve 33. This oil burner pipe 3| extends through the steel pipe 21 and has its discharge end or nozzle 34 in or near the plane of the discharge end of the flame retention nozzle or burner head I9. Suitable formations such as 35, 3B, serve to center the oil burner pipe 3| in said steel pipe or sleeve 21 near the nozzle end. A suitable adapter 31 is provided for securing the proper relationship between the steel tube 21 and the outer end of the oil burner pipe 3|. This arrangement makes it possible to insert the oil burner pipe in, or withdraw it from, the steel tube 21 without disturbing the operation of the gas fuel burner. l

If fuel oil is being burned, it is estimated that possibly 5 to 10% of the combustion air is drawn through the gas burner, and the remaining 90% or more is admitted through the secondary air doors 25, so that regardless of which type of fuel is being burned, the combustible mixture or flame, leaving the muilie block into the furnace has approximately the same proportion of air, which in some types of furnace may be as low as above theoretical requirements.

In addition to the features of the accurate control of primary and secondary air, regardless of kind of fuel being burned, the combination of burner block and mufile block creates a, hot zone to stimulate the mixing of the gaseous fuel or atomized oil with the secondary air for the purpose of obtaining an efficient and stable fire.

Applicant does not know of any other such combination of atomizing fuel oil burner and inspirating gas burner which will give equal combustion results throughout a wide range in capacity. Heretofore combination burners have functioned fairly satisfactorily as inspirating gas burners only, but the fuel oil burner feature was not satisfactory in that it was not possible to operate on as small a quantity of combustion air with fuel oil as with fuel gas. Also, the oil nre caused smoke and was very unstable in its operation due to poor mixing of atomized oil and combustion air.

What I claim is:

1. A combined gas and oil burner, comprising a tubular body, means for introducing gas and primary air into the intake end of said body, a burner head at `the other end of said body, an oil atomizer delivering to the region of discharge of the burner head, a burner block for receiving the discharge from the burner head, a chamber for secondary air and a muille block spaced from and coaxial with the burner block, said chamber being in open communication with the discharge end of the burner block and with the intake-end of the mume.

2. A combined gas and oil burner, comprising a tubular body. means for introducing gas and primary air into the intake end of said body, a burner head at the other end of said body, an oil atomizer delivering to the region of discharge of the burner head, a burner block for receiving the discharge from the burner head, a chamber for secondary air open to the discharge end of the burner block, said chamber provided with air-inlet ports and adjustable closures therefor, and a mufile block spaced from and co-axial with the burner block for receiving and delivering the discharge from the burner head mixed with the said secondary air.

3. A combined gas and oil burner, comprising a tubular body, means for introducing gas and primary air into the intake end of said body, a burner head at the other end of said body, an oil atomizer delivering to the region of discharge of the burner head, a burner block coaxial with the burner head, and positioned to receive the discharge from the said burner head, a muille block spaced from, and positioned coaxially with the burner block to receive the discharge from said burner block, and a secondary air chamber delivering to said muilie, said chamber surrounding the'burner block and partaking of the heat therefrom.

4. A combined gas and oil burner, comprising a tubular body, means for introducing gas and primary air into the intake end of said body, a burner head at the other end of said body, an oil atomizer delivering to the region of discharge of the burner head, and a tubular housing in xed axial relationship with the burner head and adapted to receive the oil atomizer and permit its insertion and withdrawal in and from the housing without disturbing the operation of the gas fuel burner.

5. A combined gas and oil burner, comprising a tubular body, means for introducing gas and primary air into the intake end of said body, a burner head at the other end of said body, an oil atomizer delivering to the region of discharge of the burner head, a burner block co-axial with the burner head, and positioned to receive the discharge from the said burner head, a munie block spaced from, and positioned co-axially with the burner block to 4receive the discharge from said burner block, and a secondary air chamber delivering to said muille, said chamber surrounding the burner block and partaking of the heat therefrom.

6. A combined gas and oil burner, comprising a tubular body, means for introducing gas and primary air into the intake end of said body, a burner head at the other end of said body, an oll atomizer delivering to the region of discharge of the burner head, a burner block co-axial with the biu'ner head, and positioned to receive the discharge from the said burner head, a mufile block spaced from, and positioned co-axially with the burner block to receive the discharge therefrom, and a secondary air chamber delivering to said muflie, said chamber provided with airintake openings above and below said burner block with independently operated closures therefor as means whereby the secondary air may receive different degrees of heat at selected zones, before entering the muille block.

W'ILIlAM FERGUSON. 

